Electromagnetic braking mechanism for elevator-cars.



H. M. P. MURPHY. ELECTROMAGNETIC BRAKING mnemmsm r011 ELEVATOR CARS.

APPLICATION FILED JUNE 9, 1910.

981,671 Patented Ja1117,1911.

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H. M. P. MURPHY. ELECTROMAGNETIC BRAKING MECHANISM FOR ELEVATOR CARS.

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981,671. Patented Jan. 17,1911.

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H. M. P. MURPHY. ELECTROMAGNETIC BRAKING MECHANISM FOR ELEVATOR CARS.

APP LIGATION II LBD JUNEQ, 1910.

Patented Jan. 17, 1911.

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H. M. P. MURPHY.

ELECTROMAGNETIC BRAKING MECHANISM FOR ELEVATOR (JARS.

APPLICATION FILED JUNE 9, 1910.

Patented J an. ,17, 1911.

5 SHEETS-SHEET 4.

woe/Mon win m2 was 7 H. M. P. MURPHY. ELECTROMAGNETIC BRAKING MECHANISMFOR ELEVATOR CARS.

I APPLICATION FILED JU-HI19, 1910. Jan 5 SHEETS-SHEET 5.

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"UNITED sTAa s PATENT OFFICE.

HOWARD M. 1?. MURPHY, OF SCARSDALE, NEW YORK, ASSIGNOR TO LE ROY CLARK,OF NEW YORK, N. Y.

ELECTROMAGNETIC BRAKING MECHANISM FOR ELEVATOR CARS.

T 0 all whom it may concern:

Be it known that I, HOWARD M. P. MUR- rnY, a citizen of the UnitedStates, residing at Scarsdale, in the county of \Vestchester and Stateof New York, have invented certain new and useful Improvements inElectromagnetic Braking Mechanism for Elevator-Cars, of which thefollowing is a full, clear, and exact description.

My invention relates to braking mechanism for elevators, the object ofthe same being to provide an electromagnetic device of this kind whichis adapted to be auto matically thrown into operation when the speed ofthe car in either direction exceeds a certain predetermined limit, orwhen the hoisting cable or plunger breaks, which is also adapted to bemanually thrown into operation fromv a point inside the car, or outsidethereof, and which may be partially released for the purpose ofpermitting the car to descend slowly and safely to one of the floors inorder to permit the passengers to leave the car.

In carrying out the invention I provide, preferably upon opposite sidesof the car, a pair of electro-magnets, which, with certain of the partsconnected thereto and operated thereby, are flexibly supported from thecar, so that independent movement between the car and said magnets ispermitted. The core of each magnet is so shaped and disposed that itwill cooperate with a fixed armature extending longitudinally of theelevator shaft, so that when the magnet is energized a retarding effectwill be produced on the magnet which, through a system of levers, willbe transmitted to gripping devices cooperating with the guide rails orother fixed parts with sufficient force to arrest or entirely stop themovement of the car in either direction.

The details of the invention will hereinafter appear, and the novelfeatures thereof will be set forth in the claims.

In the drawings forming part of this specification: Figure 1 is anelevation of an elevator car showing my improvements applied thereto;Fig. 2 is a similar view taken at right angles to Fig. 1; Fig. 3 is asectional elevation, on an enlarged scale, of one of the magnets and theleverage system between it and the brake-shoes; Fig. 4 is a similar viewtaken at right angles to Fig. 3; Fig. 5 is a view similar to Fig. 3,showing a modified Specification of Letters Patent.

Application filed June 9, 1910.

Patented Jan. 17, 1911.

Serial No. 566,099.

construction; Fig. 6 is a detail side elevation, partly in section, ofone of the magnets and its core disconnected from the other parts; Fig.7 is a section on the line 7-7 of Fig. 6, and Fig. 8 is a diagrammaticview of the circuit connect-ions.

Like reference numerals indicate like parts in the different Views.

The elevator car 1 is movable in the usual manner in the shaft 2 inwhich are located the iron or steel T-rails 3. These rails may be theordinary guide rails for the car 1, or they may be separate andindependent therefrom. Secured to each side of the car adjacent to therails 3 is a bracket 4 upon which are fulcrumed the angle levers 5.These levers are pivoted at their upper ends to the gripping devices 6,shown in the form of the usual brake-shoes, which are adapted to engageopposite sides of the adjacent rail 3. Flexibly supported upon each ofthe brackets 4 is an electro-magnet 7 whose core 8 extends through theopposite ends thereof and is provided with lateral bifurcated shoes 9which embrace and lie in close relation to the rail 3. The particularmeans shown for flexibly connecting the magnet 7 to the bracket 4consists of a spring 10 which is attached at its upper end to a lateralarm 11 on the bracket 4 and at its lower end to the core 8. The lowerends of the levers 5 are respectively pivoted to the links 12 which arein turn pivoted to the triangular plate 13 of non-magnetic material,such as brass. The upper end of the plate 13 is pivoted to the lower endof the core 8 which is formed with a yoke 14, between the branches ofwhich the plate 13 is located.

The braking mechanism comprises a mag net '7 on each side of the car,its core 8 with the laterally extending shoes 9, the rail 3 whichconstitutes an armature for the magnet 7, the brake shoes 6 adapted toengage the rail 3, and the link and lever connections between the coreof the magnet 7 and said brake shoes. The flexible connection betweenthe car and the magnet, through the spring 10, provides for the movementof the magnet with the car under normal conditions, and for independentmovement of the ear with respect to said magnet when the movement of themagnet with the car is arrested by extraneous forces.

The shoes 9 on the core 8 of the magnet 7 have been described asbifurcated and as straddling or embracing the rail 3. To obtain the mostperfect action between the magnet core and the rail 3, I prefer to formone side of the shoes 9 of a plate 15 of brass or other nonmagneticmaterial. This construction is clearly shown in Fig. 7 of the drawings.By the use of this plate on one side of each of the shoes 9, themagnetic attraction between said shoes and the rail 3 is prevented fromproducing a neutral effeet, which would be caused if both sides of theseshoes were made of iron or other magnetic material.

Constructed as above described, it will be seen that under normalconditions when the car 1 is moving up and down in the elevator shaft 2all of the parts of the braking mechanism will be carried thereby andwill be in substantially the same positions as are shown in Figs. 3 and1 of the drawing. That is to say, the magnet 7 will be held as fardownwardly away from its point of attachment to the car 1 as the spring10 will permit, and the brake shoes or gripping devices (3 will be heldout of contact with the rail 3. Free movement between the shoes 9 on themagnet core 8 and the rail 3 will also be permitted. If, however, themagnet 7 be energized, a magnetic circuit will be closed through thecore 8, the shoes 9 thereon, and the rail 3, substantially as shown bythe arrows in Fig. (3 of the drawing. The shoes 9 will thus be drawntoward the outer edge of the rail 3 and also toward one face of thesame. The result will be that the magnet 7 through its core will belocked to the rail 3 and held against upward or downward movement. Ifthe car 1 be descending, due to a breakage of the hoisting cable or fromany other cause, its downward movement will be continued slightlyindependent of the magnet. The links 12 will then be thrown outwardly,imparting a corresponding movement to the lower arms of the levers 5,and the upper arms of said levers will be moved inwardly forcing thebrake shoes 6 into engagement with the rail 3 with sufficient force toarrest the further down ward movement of the car.

Under some conditions it is advisable to provide means for checking orarresting the movement of the car when it attains :1 dangerous rate ofspeed in an upward direction. This is particularly true of elevators ofthe plunger type. In order to provide for this, the construction shownin Fig. 5 of the drawing has been designed, this construction operatingupon the same principle as that heretofore described, but providing forthe application of the braking mechanism when a dangerous speed isattained in either direction. In this construction I employ, in additionto the magnet 7, with its core 8 supported by the spring 10 upon thebracket 1 on the car and connected through the links 12 and levers 5with the brake shoes 6, a supplemental bracket 15, which is secured tothe car at the point below that to which the bracket 4 is attached, andmount thereon the levers 16 which are similar to the levers 5, butreversely disposed, and connect the lower arm of said levers withsupplemental brake shoes 17 cooperating with the rail 3, and alsoconnect the upper arms of the levers 16 with the links 18 which are inturn pivoted to the brass plate 13. If the car be descending and themagnet 7 be energized, the operation of this form of my device is thesame as that heretofore described; that is, the upper brake shoes 6 areforced into gripping engagement with the rail 3 with sufiicient force tostop the movement of the car. If, however, the car be moving upwardly,the action as follows: When the magnet 7 is energized the core 8 thereofis held against or locked to the rail 3, in the manner heretoforedescribed, and the car continues its upward movement independently ofsaid magnet. As the plate 13 is also held against move ment, the links18 are thrown outwardly, a similar movement is imparted to the up perarms of the levers 1G and the lower arms of said levers are movedinwardly, forcing the brake shoes 17 into engagement with the rail 3 andthereby arresting or checking the further upward movement of the car.

It is intended that the braking mechanism described shall beautomatically thrown into operation upon the breakage of the hoistingcables or plunger-s and also when the speed of the car exceeds apredetermined value in either direction. To provide for the first ofthese actions I propose to employ a normally open switch controlling thecircuit through the magnets 7, said switch being held in its openposition by the hoisting cable or plunger, but adapted to beautomatically closed when said cable or plunger becomes inoperative. Oneform of switch suitable for this purpose has been illustrated in Fig. 8of the drawing, the same being shown applied to the hoisting cable 19and mounted on the car 1 at a point adjacent thereto. This switchcomprises the spring fingers 20, 21, mounted upon the insulating block22 and connected respectively with the wires of the circuit through themagnets 7. Cooperating with the spring fingers 20 is a metallic contactpiece 23 adapted to bridge the circuit between or electrically connectthe spring fingers 20, 21, when in retracted position. The contact piece23 is mounted on a lever 24 fulcrumed upon a bracket arm 25 on the car 1and normally urged downwardly through the action of a spring 26. Theouter or free end of the lever 24 is provided with a yoke 27 whichembraces and bears against the cable 19 when the parts of thedevice arein their normal operating positions. hen the cable 19 is intact there isof course a heavy tension thereon, and, with the yoke 27 bearing againstit, as shown in Fig. 8, the lever 24 is held in its raised position withthe contact piece 23 out of engagement with the spring fingers 20, 21 ofthe switch. In the event of a breakage of the cable 19, the tensionthereon is relieved and the same no longer acts to resist the movementof the lever 24. The spring 26 there fore acts to draw the lever 24downwardly, forcing the contact piece 23 into engagement with the springfingers 20, 21, and closing the circuit through the magnets 7. WVhenthis takes place the braking mechanism acts to arrest the movement ofthe car in the manner heretofore described.

In order to provide for stopping a car when the speed of the sameincreases beyond a predetermined limit, I provide a switch which isthrown into operation to close the circuit through the magnets 7,through the action of a governor 28 mounted at some suitable point onthe car. Any suitable form of governor may be employed, but theparticular one shown in the drawing comprises the shaft 29 having asheave 30 on one end thereof which is rotated, during the movement ofthe car 1 up and down, through the action of the weighted rope or cable31 mounted in the shaft and passing around said sheave. On the shaft 29is a fixed collar 32 and a loose collar 33, the same being connected toeach other through the links 3435 and the balls or weights 36. Connectedwith the movable collar and operated thereby is a trigger 37 shown inthe form of a bell crank lever fulcrumed to the car at 38. The switchwhich is controlled by the governor 28 may be of any suitable form buthas been shown as comprising the spring fingers 39, 40, includedrespectively in the electric circuit through the magnets 7. adapted tobe electrically connected with each other by a contact piece 41 which isnormally urged toward said fingers by the spring 42. Said cont-actpiece, however, is provided with a central extension or rod 43 which isnormally engaged by the free end of the trigger 37, the latter servingto hold said contact piece 41 out of engagement with the spring fingers39, 40. The action of this device, it is thought, will be readilyunderstood. WVhen the car 1 is at rest or is moving in the shaft at anormal rate of speed,

the parts remain in the positions shown in Figs. 1 and 8 of thedrawings. \Vhen, however, the speed of the car increases beyond apredetermined limit, to which the governor may be readily adjusted, theballs 36 of the governor are thrown outwardly by centrifugal force farenough to trip the switch and throw it into operative position. That isto say, the collar 33 is drawn toward the These spring fingers arecollar 32, thereby rocking the trigger 37 and disconnecting the free endthereof from the rod or extension 43. The spring 42 then acts to forcethe contact piece 41 into engagement with the spring fingers 39 and 40and the electric circuit is thereby closed through the magnets 7. Theseare thereby energized and the braking mechanism is thrown into operationto arrest the movement of the car, in the manner above described. Theelectric circuit through the magnets 7 may also be closed for thepurpose of arresting the movement of the car by hand operated switches44-4546, located at any suitable points. One of these switches may belocated within the car for the use of the operator, another may belocated at a different point in the car for operation by a passenger,and the third may be located at a point outside the car for operation byany one noticing a dangerous speed condition existing.

It may happen that through one or the other of the instrumentalitiesdescribed the movement of the car may be stopped at a point betweenfioors. In order to provide means for slowly and safely lowering the carto a convenient landing place for the passengers therein, 1 provide inthe circuit through the magnets 7 a rheostat 47 by means of which theresistance in the circuit may be increased for the purpose of par tiallydeenergizing the magnets 7, thereby decreasing the effective action ofthe braking mechanism and allowing the car to gradually slip from thepoint where it originally stopped to the next floor. This rheostat maybe of any suitable construction. In the drawings 1 have illustrated thesame as consisting of the resistance coils 4S and a hand operated lever49 adapted to be moved for the purpose of throwing into the circuit agreater or less amount of resistance. The normal 110-resistance positionof the lever 49 is as shown in Fig. 8 of the drawings and the same isheld in this position by a spring 50 and a stop 51, against which thelever 49 bears. It willv be obvious that by moving the lever 49 to theleft resistance may be cut into the circuit to a greater or less degree,the effect of which is to correspondingly deenergize the magnets 7 andreduce the effective action of the braking mechanism.

The electric current for energizing the magnets 7 may be derived from astorage battery 52 located at any convenient point, or from any othersource. lilnder normal conditions the switches 44, 45, 46, 3941 and20-23, are open and there is consequently no How of current through themagnets 7. The parts of the braking mechanism. are therefore in thepositions in which they are shown in the drawings, and the car 1 is freeto move up or down in the shaft 2. If, however, the switch 2023 isclosed in the manner described, by a breakage of the hoisting cable 19,the circuit through the magnets 7 will be closed over the followingpath: battery wire 53, rheostat 47, wires al, 56, 57 and 58, finger 21,contact piece 23, finger 20 and wires 59 and 60, back to the battery. Itthe switch 39 t1 be closed through the action of the governor 29 due toexcessive speed, in the manner described, the circuit through themagnets 7 will be closed over the following path: battery 51, wirerheostat 1L7, wires 56 and 57, finger 39, contact piece -il-l finger andwire (30, back to the battery. If any one of the switches ll, t5, ill,be manually closed, the flow of current will be over the following path:battery wire rheostat JCT, wires 54, 57 5(3 and 61, and switch 44, 4-5or t6 to the wire 60, and thence back to the battery.

Having now described my invention, what I claim is:

1. The combination with an elevator car, of an electro-magnet carriedthereby, one of said parts being capable of movement inde pendent of theother, an armature for said magnet serving to produce an independentmovement of one of said parts with respect to the other when the magnetis energized, and braking mechanism connected with the car and magnetand thrown into operation upon the movement of one of said partsindependently of the other.

2. The combination with an elevator car, of an electro-magnet carriedthereby, one of said parts being capable of movement independent of theother, a fixed part constituting the armature of said magnet, andserving to hold the magnet against movement when the latter isenergized, and braking mechanism connected with said car and magnet andthrown into operation when the car moves independently of said magnet,

The combination with an elevator car, of an electro-magnet fiexiblyconnected therewith and carried thereby, a fixed armature thereforacting to arrest the movement of the magnet when the latter isenergized, and braking mechanism connected to the car and magnet andthrown into operation upon the movement of the car with respect to themagnet.

l. The combination with an elevator car, of a spring-supportedelectro-magn-et carried thereby, a fixed armature for said magnetlocated outside the car and acting to arrest the movement of the magnetwhen the latter is energized, and braking mechanism connected to the carand magnet and thrown into operation upon the movement of the car withrespect to the magnet.

5. The combination with an elevator car, of an electro-magnet carriedthereby, one of said parts being movable independently of the other, afixed armature for said magnet serving to hold the magnet againstmovement when the latter is energized, and braking mechanism comprisinggripping devices, levers fulcrumed to the car for operating the same,and connections between said levers and said magnet, whereby saidgripping devices are thrown into operation when said magnet is energizedand independent movement of the car with respect to said magnet iseffected.

(3. The combination with an elevator car, of a spring-supportedclectro-magnet carried thereby, a fixed armature for said magnet servingto arrest the movement of the magnet when the latter is energized, andbraking mechanism comprising gripping devices, levers fulcrumed to thecar for actuating the same, and connections between said levers and saidmagnet, whereby said gripping devices are thrown into operation whensaid magnet is energized and independent movement of the car withrespect to said magnet is effected.

7. The combination with an elevator car, of an electro-magnet, a springconnecting said magnet with the car and supporting the same, a fixedarmature for the magnet acting to arrest the movement thereof when thesame is energized, and braking mechanism comprising gripping devices,levers fulcrumed to the car for operating the same, and link connectionsbetween said levers and said magnet, whereby said gripping devices arethrown into operation when said magnet is energized and independentmovement of the car with respect to said magnet is effected.

S. The combination with an elevator car, of an electro-magnet flexiblyconnected therewith and carried thereby, the core of said magnet beingprovided with laterally extending shoes, a fixed armature for saidmagnet extending longitudinally of the elevator shaft and forming partof a closed magnetic circuit through said magnet when the latter isenergized, and braking mechanism connected to the car and magnet andthrown into operation upon the movement of the ear with respect to themagnet.

9. The combination with an elevator car, of an electro-magnet flexiblyconnected therewith and carried thereby, the core of said magnet beingprovided with laterally extending shoes, fixed armature for said magnetextending longitudinally of the elevator shaft and forming part of aclosed magnetic circuit through said magnet when the latter isenergized, braking mechanism comprising gripping devices, leversfulcrumed to the car for operating the same, and link connectionsbetween said levers and said magnet, whereby said gripping devices arethrown into operation when said magnet is energized and independentmovement of the car with respect to said magnet is effected.

10. The combination with an elevator car, of an electro-magnet,comprising a core having laterally extending bifurcated shoes and a coilsurrounding said core, a spring connecting the car with said magnet forsupportin the latter and providing for independent movement of the carwith respect thereto, a fixed armature extending longi tudinally of theelevator shaft, the same being embraced by the bifurcated shoes on themagnet core, and braking mechanism connected to the car and magnet andthrown into operation upon the movement of the car with respect to themagnet.

11. The combination with an elevator car, of an electro-magnet,comprising a core having laterally extending bifurcated shoes and a coilsurrounding said core, a spring connecting the car with said magnet forsupporting the latter and providing for independent movement of the carwith respect thereto, a fixed armature extending longitudinally of theelevator shaft, the same being embraced by the bifurcated shoes on themagnet core, and braking mechanism, comprising gripping devices, leversfulcrumel to the car and pivoted to said gripping de vices for actuatingthe latter, and link connections between said levers and said magnet,whereby said gripping devices are thrown into operation when said magnetis energized and independent movement of the car with respect to saidmagnet is effected.

12. The combination with an elevator car, of an electro-magnet flexiblyconnected therewith and carried thereby, a fixed arma ture thereforacting to arrest the movement of the magnet when the latter isenergized, and braking mechanism, comprising two sets of grippingdevices and link and lever connections between the respective grippingdevices and said magnet, whereby one set of said gripping devices willbe thrown into operation upon the movement of the car in one directionindependently of the magnet, and the other will be thrown into operationbraking mechanism connected to the car and.

magnet and thrown into operation upon the movement of the carindependently of the magnet, a switch for closing an electric circuitthrough said magnet, and means automatically thrown into operation uponderangement of the hoisting mechanism for actuating said switch.

14. The combination with an elevator car, of an electro -1nagnetflexibly connected therewith and carried thereby, a fixed armaturetherefor acting to arrest the movement of the magnet when the latter isenergized, braking mechanism connected'to the car and magnet and throwninto operation upon the movement of the car independently of the magnet,a switch for closing an elec tric circuit through said magnet, and meansautomatically thrown into operation when the car exceeds a certainpredetermined speed for actuating said switch.

15. The combination with an elevator car, of an electro magnet flexiblyconnected therewith and carried thereby, a fixed armature thereforacting to arrest the movement of the magnet when the latter isenergized, braking mechanism connected to the car and magnet and throwninto operation upon the movement of'the car independently of the magnet,an electric circuit through said magnet, a switch for closing saidcircuit, and a rheostat included in said circuit for cutting inresistance and permitting the ear to be slowly lowered from one point toanother.

In witness whereof, I subscribe my signature, in the presence of twowitnesses.

HOVARD M. P. MURPHY.

WVitnesses WM. M. STOCKBRIDGE, WALDO M. CHAPIN.

